#include <Eigen/Core>
#include <iostream>
using namespace Eigen;
using namespace std;

// define a custom template unary functor
template<typename Scalar>
struct CwiseClampOp
{
	CwiseClampOp(const Scalar& inf, const Scalar& sup)
		: m_inf(inf)
		, m_sup(sup)
	{
	}
	const Scalar operator()(const Scalar& x) const { return x < m_inf ? m_inf : (x > m_sup ? m_sup : x); }
	Scalar m_inf, m_sup;
};

int
main(int, char**)
{
	Matrix4d m1 = Matrix4d::Random();
	cout << m1 << endl << "becomes: " << endl << m1.unaryExpr(CwiseClampOp<double>(-0.5, 0.5)) << endl;
	return 0;
}
